Olaparib refers to 4-[(3-[(4-cyclopropylcarbonyl)piperazin-4-yl]carbonyl)-4-fluorophenyl]methyl(2H)phthalazin-1-one having the structure:

Olaparib is a phthalizinone compound developed as a poly(ADP-ribose) polymerase (PARP) inhibitor for use in treating cancers including ovarian, breast, and prostate cancers. Olaparib has been approved by the U.S. Food and Drug Administration for treatment of women with advanced ovarian cancer associated with defective BRCA genes.
Synthesis of olaparib and characterization of solids forms of the compound are disclosed in U.S. Pat. Nos. 8,247,416; 7,692,006; 8,183,369, 9,981,951, and 8,475,842. Specifically, U.S. Pat. No. 8,247,416 discloses 4-[3-(4-cyclopropanecarbonyl-piperazine-1-carbonyl)-4-fluoro-benzyl]-2H-pthalazin-1-one (Compound A) substantially in crystalline form, and in particular in Form A. This patent also discloses a method of synthesizing 4-[3-(4-cyclopropanecarbonyl-piperazine-1-carbonyl)-4-fluoro-benzyl]-2H-pthalazin-1-one from 2-fluoro-5-(4-oxo-3,4-dihydro-phthalazin-1-ylmethyl)-benzoic acid.
U.S. Pat. No. 7,692,006 discloses other methods of obtaining 4-[3-(4-cyclopropanecarbonyl-piperazine-1-carbonyl)-4-fluoro-benzyl]-2H-pthalazin-1-one (Compound A) as crystalline Form A. This patent also discloses an intermediate of 2-fluoro-5-(4-oxo-3,4-dihydro-phthalazin-1-ylmethyl)-benzoic acid (ED) useful for preparing olaparib and a method of synthesizing the intermediate.
U.S. Pat. No. 8,183,369 discloses 4-[3-(4-cyclopropanecarbonyl-piperazine-1-carbonyl)-4-fluoro-benzyl]-2H-pthalazin-1-one as crystalline Form L and a method of obtaining the form from crystalline Form A of 4-[3-(4-cyclopropanecarbonyl-piperazine-1-carbonyl)-4-fluoro-benzyl]-2H-pthalazin-1-one.
U.S. Pat. No. 9,981,951 discloses a solid described as crystalline Form B of olaparib (a hydrated crystalline form).
U.S. Pat. No. 8,475,842, discloses a solid described as crystalline Form H of 4-[3-(4-cyclopropanecarbonyl-piperazine-1-carbonyl)-4-fluoro-benzyl]-2H-pthalazin-1-one (Compound I).
Although the above-mentioned crystalline forms have been disclosed, new solid forms of olaparib are still needed for enhancing the compound's demonstrated efficacy in the treatment of cancers, as well as for improving processes for manufacture of pharmaceutical formulations containing a solid form of olaparib. The present invention meets this need, providing a novel crystalline form of olaparib and a process for preparing the crystalline form.